With the increasing integration degree of semiconductor devices and decreasingly reduction on dimensions of the devices and space between the adjacent devices, crosstalk between adjacent memory cells is more and more serious, easily causing many issues such as operating errors, and deterioration of electrical properties, etc. Therefore, how to reduce crosstalk between the adjacent memory cells becomes particularly important.
Currently, in a semiconductor memory device, dielectric between the adjacent memory cells is usually oxide, but the dielectric constant of the oxide is relatively large, about 3.9. To solve this issue, one method is to reduce the dielectric constant of the dielectric. That is, in fabrication processes, low dielectric constant materials are usually used to replace the dielectric with high dielectric constant, such as silicon oxide. However, when the process technology gradually evolves into smaller dimension, low dielectric constant materials have also been unable to meet the requirements.
Ideally, the dielectric constant of the dielectric can be reduced to 1.0, that is, the dielectric constant of vacuum. Therefore, a method is needed to reduce the dielectric constant of the dielectric between the adjacent memory cells to reduce the crosstalk. The disclosed device structures and methods are directed to solve one or more problems set forth above and other problems.